Coria Lorena M, Ibañez Andrés E, Tkach Mercedes, Sabbione Florencia, Bruno Laura, Carabajal Marianela V, Berguer Paula M, Barrionuevo Paula, Schillaci Roxana, Trevani Analía S, Giambartolomei Guillermo H, Pasquevich Karina A, Cassataro Juliana
Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, Universidad Nacional de San Martín, Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, 1650 Buenos Aires, Argentina;
Laboratorio de Mecanismos Moleculares de Carcinogénesis, Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, 1428 Buenos Aires, Argentina;
J Immunol. 2016 May 15;196(10):4014-29. doi: 10.4049/jimmunol.1501188. Epub 2016 Apr 15.
In this study, we demonstrate that the unlipidated (U) outer membrane protein (Omp) 19 from Brucella spp. is a competitive inhibitor of human cathepsin L. U-Omp19 inhibits lysosome cathepsins and APC-derived microsome activity in vitro and partially inhibits lysosomal cathepsin L activity within live APCs. Codelivery of U-Omp19 with the Ag can reduce intracellular Ag digestion and increases Ag half-life in dendritic cells (DCs). U-Omp19 retains the Ag in Lamp-2(+) compartments after its internalization and promotes a sustained expression of MHC class I/peptide complexes in the cell surface of DCs. Consequently, U-Omp19 enhances Ag cross-presentation by DCs to CD8(+) T cells. U-Omp19 s.c. delivery induces the recruitment of CD11c(+)CD8α(+) DCs and monocytes to lymph nodes whereas it partially limits in vivo Ag proteolysis inside DCs. Accordingly, this protein is able to induce CD8(+) T cell responses in vivo against codelivered Ag. Antitumor responses were elicited after U-Omp19 coadministration, increasing survival of mice in a murine melanoma challenge model. Collectively, these results indicate that a cysteine protease inhibitor from bacterial origin could be a suitable component of vaccine formulations against tumors.
在本研究中，我们证明了来自布鲁氏菌属的未脂质化（U）外膜蛋白（Omp）19是人类组织蛋白酶L的竞争性抑制剂。U-Omp19在体外抑制溶酶体组织蛋白酶和抗原呈递细胞（APC）来源的微粒体活性，并部分抑制活APC内的溶酶体组织蛋白酶L活性。将U-Omp19与抗原共同递送可减少细胞内抗原消化，并延长其在树突状细胞（DC）中的半衰期。U-Omp19内化后将抗原保留在Lamp-2(+)区室中，并促进DC细胞表面MHC I类/肽复合物的持续表达。因此，U-Omp19增强了DC向CD8(+) T细胞的抗原交叉呈递。皮下递送U-Omp19可诱导CD11c(+)CD8α(+) DC和单核细胞募集至淋巴结，同时部分限制DC内的体内抗原蛋白水解。因此，该蛋白能够在体内诱导针对共同递送抗原的CD8(+) T细胞应答。在共同施用U-Omp19后引发了抗肿瘤反应，在小鼠黑色素瘤攻击模型中提高了小鼠的存活率。总的来说，这些结果表明，一种源自细菌的半胱氨酸蛋白酶抑制剂可能是抗肿瘤疫苗制剂的合适成分。
